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@@ -0,0 +1,40 @@
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+\documentclass[varwidth=true, border=2pt]{standalone}
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+
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+\usepackage{pgfplots}
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+\usepackage{tikz}
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+
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+\begin{document}
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+\begin{tikzpicture}
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+ \begin{axis}[
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+ legend pos=south west,
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+ axis x line=middle,
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+ axis y line=middle,
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+ grid = major,
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+ %width=9cm,
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+ %height=9cm,
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+ grid style={dashed, gray!30},
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+ xmin=-1.5, % start the diagram at this x-coordinate
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+ xmax= 1.5, % end the diagram at this x-coordinate
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+ %ymin=-0.25, % start the diagram at this y-coordinate
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+ %ymax= 2.25, % end the diagram at this y-coordinate
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+ axis background/.style={fill=white},
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+ xlabel=$x$,
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+ ylabel=$y$,
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+ %xticklabels={-2,-1.6,...,7},
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+ %yticklabels={-8,-7,...,8},
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+ tick align=outside,
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+ minor tick num=-3,
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+ enlargelimits=true,
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+ tension=0.08]
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+ \addplot[domain=-1.5:1.5, red, thick,samples=50] {x*x};
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+ \draw[blue, thick] \pgfextra{
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+ \pgfpathellipse{\pgfplotspointaxisxy{0}{1}}
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+ {\pgfplotspointaxisdirectionxy{0.87}{0}}
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+ {\pgfplotspointaxisdirectionxy{0}{0.87}}
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+ % see also the documentation of
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+ % 'axis direction cs' which
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+ % allows a simpler way to draw this ellipse
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+ };
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+ \end{axis}
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+\end{tikzpicture}
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+\end{document}
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